A variety of catheters for delivering a therapy and/or monitoring a physiological condition have been implanted or proposed for implantation in patients. Catheters may deliver therapy to, and/or monitor conditions associated with, the heart, muscle, nerve, brain, stomach or other organs or tissue. Many catheters are tracked through the vasculature to locate a therapeutic or diagnostic portion of the catheter at a target site. Such catheters must have flexibility to navigate the twists and turns of the vasculature, sufficient stiffness in the proximal portion thereof to be pushed through the vasculature alone or over a guidewire or through a lumen, and the capability of orienting a distal portion thereof in alignment with an anatomical feature at the target site so that a diagnostic or therapeutic procedure can be completed. In general terms, the catheter body must also resist kinking and be capable of being advanced through access pathways that twist and turn, sometimes abruptly at acute angles.
The distal portions of catheters frequently need to be selectively deflected or bent and straightened again while being advanced within the patient to steer the catheter distal end into a desired body lumen or chamber. For example, it may be necessary to direct the catheter distal end through tortuous anatomies and/or into a branch of vessel bifurcation. In addition, some procedures require high accuracy in guidewire orientation. For example, when a subintimal approach is selected for crossing a Chronic Total Occlusion (CTO), a guidewire needs to be accurately oriented to re-enter the true vessel lumen downstream of the CTO. Various steerable mechanisms have been disclosed to steer catheters and other elongated medical devices, e.g., steerable guidewires and stylets, and often involve the use of a deflection mechanism extending through a lumen of the catheter body to an attachment point in the catheter distal portion. For example, a deflection mechanism may include elongated wires referred to as control or pull wires, extending between a proximal control mechanism and the distal attachment point. More complex steerable catheters have two or more lumens and control wires extending from the handle to different points along the length or about the circumference of the catheter body to induce bends in multiple segments of the catheter body and/or in different directions.
Embodiments hereof are directed to a catheter having deflectable tip for navigating through or within a patient's anatomy.